Pointer to user's storage for number of bytes actually received from the host. This will be valid upon the subsequent USBX_RX_COMPLETE call-back.

Returns

This function returns a status word. 0 indicates that the read was successfully started. Any other value indicates that the request was ignored. The most common reason is USBX_STATUS_EP_BUSY meaning that a read is already in progress.

A USBX_RX_COMPLETE call-back will occur when the read transfer has completed. For example if the user reads a block of 100 bytes, two packets will be received (one 64 byte packet and one 36 byte packet), but the USBX_RX_COMPLETE call-back will only occur after the final packet has been received.

If the device receives more data than the value specified by numBytes, the USBX_RX_COMPLETE call-back will occur when numBytes number of bytes has been received. At this point, the USBX_RX_OVERRUN status flag will also be set, indicating that more data was received than is available to write to the buffer at block. At this point, the application may call USBX_blockRead() again to receive the remaining data from the transfer.

This function utilizes the EFM32 USB Library's USBD_Read() function, which only prepares for a read. The actual read will occur over time as the host transmits data.

Pointer to user's storage for number of bytes actually transmitted to the host. This will be valid upon the subsequent USBX_TX_COMPLETE call-back.

Returns

This function returns a status word. 0 indicates that the write was successfully started. Any other value indicates that the request was ignored. The most common reason is USBX_STATUS_EP_BUSY meaning that a write is already in progress.

A USBX_TX_COMPLETE call-back will occur when the entire transfer has completed. For example if the user writes a block of 100 bytes, two packets will be sent (one 64 byte packet and one 36 byte packet), but the USBX_TX_COMPLETE call-back will only occur after the final packet has been sent.

This function utilizes the EFM32 USB Library's USBD_Write() function, which only prepares for a write. The actual write will occur over time as the host transmits data.

Returns an 32-bit value indicating the reason(s) for the API call-back, and clears the USBXpress API call-back pending flag(s). This function should be called at the beginning of the user's call-back service routine to determine which event(s) has/have occurred.

Returns

An unsigned 32-bit code indicating the reason(s) for the API interrupt. The code can indicate more than one type of interrupt at the same time. Valid flags are found in USB Status Flags